/*
 *    Copyright 2009-2012 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.mapping;

import org.apache.ibatis.executor.BaseExecutor;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Map;
import java.util.Properties;

/**
 * Vendor DatabaseId provider
 * <p>
 * It returns database product name as a databaseId If the user provides a
 * properties it uses it to translate database product name
 * key="Microsoft SQL Server", value="ms" will return "ms" It can return null,
 * if no database product name or a properties was specified and no translation
 * was found
 * @author Eduardo Macarron
 */
public class VendorDatabaseIdProvider
        implements DatabaseIdProvider {

    private static final Log log = LogFactory
            .getLog(BaseExecutor.class);

    private Properties properties;

    public String getDatabaseId(
            DataSource dataSource) {
        if (dataSource == null)
            throw new NullPointerException(
                    "dataSource cannot be null");
        try {
            return getDatabaseName(dataSource);
        } catch (Exception e) {
            log.error(
                    "Could not get a databaseId from dataSource",
                    e);
        }
        return null;
    }

    public void setProperties(
            Properties p) {
        this.properties = p;
    }

    private String getDatabaseName(
            DataSource dataSource)
            throws SQLException {
        String productName = getDatabaseProductName(dataSource);
        if (this.properties != null) {
            for (Map.Entry<Object, Object> property : properties
                    .entrySet()) {
                if (productName
                        .contains((String) property
                                .getKey())) {
                    return (String) property
                            .getValue();
                }
            }
            return null; // no match, return null
        }
        return productName;
    }

    private String getDatabaseProductName(
            DataSource dataSource)
            throws SQLException {
        Connection con = null;
        try {
            con = dataSource
                    .getConnection();
            DatabaseMetaData metaData = con
                    .getMetaData();
            return metaData
                    .getDatabaseProductName();
        } finally {
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    // ignored
                }
            }
        }
    }

}
